Altimeter regulator



I June 29, 1943.

A. URFER ALTIMETER REGULATOR Filed March 7, 1942 2 Sheets-Sheet lINVENTOR:

A. URFER TTORNEYS WW w June 29, 1943. A, URFER ALT IMETER REGULATORFiled March 7, 1942 2 Sheets-Shet 2 INVENTOR A. URFER BY i v ATTORNEYSPatented June 29, 1943 U N i T E D STAT E S FATE N T OFFICE ALTIMETERREGULATOR Adolf Urfer, New Rochelle, N. Y.

ApplicationlVIarch 7, 1942, Serial No. 433.759

Claims.

This invention relates to altimeters for aircraft.

Objects and advantages of the invention will be set forth in parthereinafter and in part will be obvious herefrom, or may be learned bypractice with the invention, the same being realized and attained bymeans of the instrumentalities and combinations pointed out in theappended claims.

The invention consists in'the novel parts, constructions, arrangements,combinations and improvements herein shown and described.

The accompanying'drawings, referred to herein and constituting a parthereof, illustrate one embodiment of the invention, and together withthe description, serve to explain the principles of the invention.

Of the drawings:

Fig. l is a front elevation of an altimeter embodying the invention,showing the zero setting of th dials;

Fig. 2 is a similar view showing a different setting of the dials;

Fig. 3 is an enlarged vertical section on line 3-3 of Fig. 1;

Fig. 4 is a rear plan detail of the larger dial showing the cam trackthereon;

Fig. 5 is a section on line 55 of Fig. '4;

Fig. 6 is a section on line 6-6 of Fig. 3;

Fig. '7 is a detail plan view of the smaller dial;

Fig. 8 is a section on line 88 of Fig. 7; and

Fig. 9 is a detail plan view of the face plate.

Objects of the invention are to provide an improved barometric altimeterhaving means for manuallysetting inadvance the altitude of the intendedlanding field or the altitude of any other known spot so that thefigures indicated by the altimeter will be those of the actual distancefrom the ground at such spot, thereby saving the pilot from having tomake the necessary mental calculations on each observation of theinstrument. Such manual or arbitrary settings or corrections are alsodesirable to compensate for changes in barometric pressures. Theinvention includes means for'automatically registering and indicatingzones of altitude beyond those in the range of the large scale dial sothat the pilot will automatically be presented with visibl indiciashowing the actual altitude within ranges very much greater than that ofthe large scal graduations of the indicator dial. Another object of theinvention is to maintain constant registration and coordination betweenthe .positions and indicia of the major indicating dial and the minor orsmall scale indicator so that the pilot can tell at a glance what hisactual altitude may be regardless of any arbitrary or manual settingswhich have been applied to the instrument.

In connection with the latter object of the invention I provid a verysimple mechanism for maintaining constant the ratios of movement betweenthe twoscales or dials, which means are very accurate and without anylooseness or lost motion in the setting operations. Another feature ofthe invention is the provision of means for preventing mis-alignment ofany of the scales or dials through inadvertent settings thereof in thewrong directionor opposite sense from that required for properoperation.

More particularly my invention provides means in a barometric altimeterfor applying arbitrary or manual corrections to an altimeter scale ordial and for transferring such correc tions automatically and-in theproper ratio to a smaller scale indicator so that when the range of themajor indicator scale has been exceeded by'such arbitrary corrections,such excess movement will be automatically indicated on the smallerscale dial thereby providing the pilot with a constant record andindication of the actual amount of ground elevation subtracted from thebarometric reading of the instrument. -By this means the instrument canbe set over a very large range of altitudes for giving true heightreadings from the ground which can be read=directly from the altimeter.

It will be understood that the foregoing general description and thefollowing detailed description as well are exemplary and explanatory butare not restrictive of the invention. Referringnow in detail to thepresent preferred embodiment of the invention, illustrated by way ofexample in the accompanying drawingsya barometric altimeter ofg'enerally'known construction is shown having acylindrical cup-likeouter casing l in which is verticallymounted a triangular mainsupporting bracket 2 by means of screws 3 formed in'lugs 4 extendinginwardly from the cylindrical wall' of the casing. The front open faceof the casing I is preferably sealed by a transparent closure such asthe glass plate lllll which isheldinplacebyth expanding split ring IN. Ahigh-vacuum diaphragm or capsule 5 is mountedfor vertical expansion andcontraction within the casing, the bottom end 6 thereofbeing supportedfrom the projecting bracket I of the main bracket 2. An-adjusting-screw8 may be provided in said bracket 1 for compensating for seasoning ofthe diaphragm or warpage of the mechanism.

Means are provided for multiplying the motions from expansion andcontraction of the capsule and for transmitting said multiplied motionsto a pointer or other indicator in known manner. As embodied a pointeror hand I is mounted at the end of horizontal shaft H, said pointerbeing adapted to be turned by said shaft in a vertical plane at thefront of the altimeter. The front end of shaft H projects from a sleevebearing bushing l2 formed in the main bracket 2. The shaft ll projectsrearwardly therefrom and its main end is supported in a smaller sizedbearing bushing l3. The latter is supported in a rearwardly extendingU-shapecl bracket I4 which is mounted on the rear face of the mainbracket 2.

The embodied means for transmitting vertical motion of the capsule 5 torotate shaft II and pointer l0 at a multiplied rate comprises anupstanding arm fixed to the upper surface of the capsule. The upper endof said arm 2'0 is pivotally connected at 2| to a pivoted cross-link 22,the short end of which is fulcrumed at 23, while the longer arm thereofis pivotally connected at its end 24 to an upwardly extending link 25.The latter is connected to transmit angular motion to the upperhorizontal shaft 26 by means of a sleeve 21 which is attached to turnwith said shaft and is provided with angularly extending arm 28 to whichthe upper end of link is pivotally connected. The upper horizontal shaft26 is journalled at its rear end by means of a sleeve bushing bearing 29which is journalled in the rear wall of an L-shaped bracket 30 extendingrearwardly from the rear face of the main bracket 2. The front end ofshaft 26 is similarly mounted by means of sleeve bearing bushing 3|which is journalled in the main bracket 2. A pointer or hand forindicating the relatively small angular motion of shaft 26 is mounted atthe front end thereof and rotates in a vertical plane parallel to andinside that of the pointer I0.

The embodied means for transmitting multiplied rotary movement fromshaft 26 to pointer shaft ll comprises a geared segment 38, theperipheral teeth of which are positioned to engage a pinion 39 fixed onthe shaft II. Said segment is provided with a hub 40 sleeved on theshaft 26 and fixed to turn therewith by a set screw or other suitablemeans. Thus it will be evident that vertical movements of the expandedand contracted capsule 5 will be translated into rotary movement of theshafts 26 and II and that the ratio of the rotary movements thereof willbe determined by the gear ratios of the segment 38 and pinion 39. Meansfor preventing erratic movements of the pointer shafts, as from shakingor jarring of the instrument, comprises a light spring 45, the lower endof which is fixed to the bracket l4 and the upper end to an arm 46 whichprojects from the sleeve 21 on shaft 26. It will thus be clear that thelarge hand IE! will rotate at a higher angular rate than the smallerhand 35.

In accordance with the invention graduated scales are provided forregistering the movements of the pointers l0 and 35 in terms of altitudein feet. As embodied, a circular face plate 50 is centrally apertured at5! to fit about the projecting end of the shaft ll, said plate beingseated firmly against the forward face of the clockwise.

main bracket 2 and held there by set screws 53 or other suitable means.A small diameter dial 55 is provided for registering movements of thepointer 35. Said dial 55 is apertured at 56 to fit about the projectingend of bushing 3| of shaft 26 and the face plate 50 is apertured at 51loosely to surround the dial 55 which thus lies in the same plane as theface plate and against the face of the main bracket 2.

The embodied means for registering the greater movements of the hand 10comprises a graduated dial or ring 60 which is mounted parallel to andin front of the face plate 50 and spaced therefrom by the cam track 6|which is riveted to and projects from the inner or rear face of dial 60for the purpose hereinafter described. The ring 60 is rotatively mountedwithin the casing 2 and held in vertical alignment in its rotative pathby a plurality of pins 62 projecting inwardly from the casing 2 in frontof the ring and by light contact of cam 6| against the face plate 50. Aswill be clear from Fig. 3 the external diameter of the ring dial 60 issubstantially equal to that of the face plate 50, while the interiordiameter forms an opening sufficiently large to clear the lower half ofthe smaller dial 55 as shown in Fig. 1. The front face of dial 60 issuitably graduated in angular sub-divisions and as shown is adapted toindicate changes in altitude over a range of 3000 ft. for one completerevolution of the hand I0. A portion of the lower exposed segment of thesmaller dial 55 is angularly graduated to show a total range of 9000ft., each sub-division being for 3000 ft. and thus equal to one completerevolution of the larger hand l0.. Thus it will be clear that thesmaller dial 55 with hand 35 will serve to register the gross altitudechanges and thereby indicate automatically to the observer the 3000 ft.stratum within which minute changes ar indicated by the hand ID on dial60.

In accordance with the invention means are provided for impartingarbitrary settings to the dial 60 so as automatically to compensate forbarometric pressure variations and for the differences in altitudebetween the point of take-ofi and the point of intended landing or othersignificant points with which the flight may be concerned. Moreover, theinvention provides means for automatically communicating such arbitrarymovements or correction settings to the smaller dial 55 so that anysetting of the larger dial will automatically be communicated to thesmaller in the proper ratio. For the purpose of setting the larger dial,same is rotatably and frictionally supported by a friction clutchcomprising the flared plates 65 and 66 on the manually turnable knobshaft 61 which is mounted in the boss 68 at the bottom of the casing l.A suitable knob 69 is provided for turning shaft 61 and as will be clearthe motion thereof is transmitted to dial 60.

For example, as shown in Figs. 1 and 2, counter-clockwise rotation ofknob 69 turns dial 60 Fig. 2 shows an arbitrary setting of 1500 ft. hasbeen imparted to the dial 60. Such a setting would be made when theairport at which landing was intended to be made had an actual altitudeof 1500 ft. above sea level. The position of the hand ID in Fig. 2 thusindicates to the pilot that the plane is flying at an elevation of 500ft. above the airport, although the plane is actually flying at anelevation of 2000 ft. above sea level. It will also be noted in Fig. 2that the smaller dial 55 has been turned from the register point by anamount corresponding to the arbitrarysettingof 1500 ft. on the largerdial 60. Thus the pilot by glancing at the arrow 35 can instantlyevaluate his altitude above the airport as 500 ft.

In accordance with the invention the arbitrary setting imparted to thedial 6!) is transferred in the proper ratio to the dial 55 by meanswhich are simple, positive and essentially foolproof. For this purposethe front face of the dial 55 is provided with a series of pins 15 15and 15 which are spaced angularly from each other distancescorresponding to the graduations on the dial. The rear face of dial 60,as previously mentioned, is provided with a cam track 6| which projectsrearwardly into the space between dial 60 .and the face plate 50 and isdisposed to cooperate with the pins 15 on dial 55. Said cam track 6! islaid out as a progressive spiral-ofone revolution, the space between theouter end I! and the inner end 18 being equal to the distance betweenany pair of the pins 15. In the zero or starting position of the dials,indicated in Fig. 1, the uppermost pin l5 thus lies against the outsideperimeter of the cam track and near the inner end 18 thereof. Rotationof the dial 60 by means of the knob 69 thus forces the pin upwardly sothat, in the position of Fig. 2, the uppermost pin has been moved by thecam track a distance equal to one-half that of the space between thepins, i. e., a distance of 1500 ft. as represented on the small scale ofdial 55. Other arbitrary movements of the dial 60 in either directionwill thus set off a corresponding movement on the small dial 55. Incases where the arbitrary setting on the larger dial exceeds a completerevolution (i. e. 3000 ft.), the next pin 15* in the series will bepicked up by the end 18 of the cam track and thereafter the cam will actupon said second pin for the next revolution of the dial 60 and so on.

It will be noted that the ends of the spiral cam track 6| are beveled soas easily to initiate positioning thereof with respect to the pins 15.Moreover the outer end 11 of the cam track overlaps the inner end 18thereof so that in shifting from one pin to the next there will never beany slippage or dislocation. That is, the second pin "l5 will be pickedup by the inner end 18 of the cam track before the outer end 11 hascleared the uppermost pin 15 Means are provided for causing the pins 15to bear against the outer perimeter of the cam track 6| during rotationthereof. For this purpose a tension spring 80 is fixed at 8! on the mainbracket 2 and its opposite end is attached to an eccentric pin 82 on therear face of the dial 55. Thus the normal tendency of the spring 80 isto urge dial 55 to rotate in counter-clockwise direction (Fig. 6) andthus force the appropriate pin 15 to bear against the outer edge orperimeter of the cam track.

The invention also provides means for guarding against mis-alignment ofthe pin 15 and cam track 6| due to an inadvertent turning of the dial 60in the wrong direction. This incorrect turning is apt to be done by theuser especially when the dials are near or at their zero setting. FromFig. 1 it will be noted that rearward or counter-clockwise turning ofdial 60 would cause the uppermost pin [5 to slip past the inner'end 78of the cam track and thereafter the normal tendency would be to spin orturn dial 55 in clockwise direction (Fig. 1) under the influence of thespring 80 and there would be nothing to prevent it from slipping awayfrom any contact with the cam track. In accordance with the inventionsuch incorrect turning of the dial 55 is counteracted by means of thespring 80. 'As shown (Fig. 6) the spring lies across the upper corner ofthe bracket member 30. Ordinarily as hereinabove explained, the pull ofthe spring 80 is horizontal; However, when the dials -60 and 55 areturned in the wrong direction from the zero point (counter-clockwise inFig. 6), the pin 82 will drop below the level of the upper edge ofbracket 30, thereby causing spring 80 to bend about the 'upper innercorner C of said bracket 30, i. e. into direction of pull of the spring80. Consequently I provide a flexible or resilient limitation againstturning of the dials in the wrong direction from the zero point andthereby prevent mis-alignment of the pins 15- on the cam track 6| aspreviously explained.

The invention in its broader aspects is not limited to the specificmechanisms shown and described but departures may be made therefromwithin the scope of the accompanying claims without departing from theprinciples of the invention and without sacrificing its chiefadvantages.

What I claim is:

1. In an altimeter in combination a rotatable dial for registering smallchanges in altitude, a second rotatable dial for registering grossdivisions of altitude, means for arbitrarily turning said first dial toapply selected factors to the altitude registrations thereof, the seconddial being in a plane parallel to and spaced from that of the first dialand rotatable on an axis eccentric to that of the first dial, and a cammovable with the first dial, means on the second dial engaging said camto turn said second dial an amount proportionate to the turning of thefirst dial.

2. In an altimeter in combination a rotatable graduated dial forregistering small changes in altitude, a second rotatable graduated dialfor registering gross divisions of altitude, the second dial being in aplane parallel to and spaced from that of the first dial and rotatableon an axis eccentric to that of the first dial, means for arbitrarilyturning said first dial to apply selected factors to the altituderegistrations thereof, a spiral cam track on that surface of the firstdial adjacent the second dial, cam engaging means on the second dial forrotating same as the first dial is rotated, said cam being of suchconfiguration that the dials are turned in the same proportion as thegraduations of one dial bear to the graduations of the other.

3. In an altimeter in combination a rotatable graduated dial forregistering small changes in altitude, a second rotatable graduated dialfor registering gross divisions of altitude, the second dial being in aplane parallel to and spaced from that of the first dial and rotatableon an axis eccentric to that of the first dial, means for arbitrarilyturning said first dial to apply selected factors to the altituderegistrations thereof, a spiral cam track on that surface of the firstdial adjacent the second dial, cam engaging means comprising spaced pinson the second dial for rotating same as the first dial is rotated, said,

cam being of such configuration that the dials are turned in the sameproportion as the graduations of one dial bear to the graduations of theother.

' 4. In an altimeter in combination a rotatable graduated annular dialfor registering small changes in altitude, a second rotatable graduateddisc-shaped dial for registering gross divisions of altitude, the seconddial being in a plane parallel to and spaced from that of the first dialand rotatable on an axis eccentric to that of the first dial, means forarbitrarily turning said first dial to apply selected factors to thealtitude registrations thereof, a spiral cam track on that surface ofthe first dial adjacent the second dial,

cam engaging means on the second dial for rotating same as the firstdial is rotated, said cam being of such configuration that the dials areturned in the same proportion as the graduations of one dial bear tothe'graduations of the other, the graduations on the second dial beingviewable through the annular opening of the first dial. 5. In analtimeter in combination a rotatable graduated dial for registeringsmall changes in altitude, a second rotatable graduated dial forregistering gross divisions of altitude, the second dial being in aplane parallel to and spaced from that of the first dial and rotatableon an axis eccentric to that of the first dial, means for arbitrarilyturning said first dial to apply selected factors to the altituderegistrations thereof, a spiral cam track on that surface of the firstdial adjacent the second dial, cam engaging means on the second dial forrotating same as the first dial is rotated, said cam being of suchconfiguration that the dials are turned in the same proportion as thegraduations of one dial bear to the graduations of the other, andresilient means for opposing turning of the second dial in onedirection.

ADOLF URFER.

